Well, I came from Sky to Tivo, and yes it is very different and much more complicated. But I think that is becuase of all the extra functionality it has. I found it difficult at first, but once I'd taken the time to go through the tutorials, it is easy enough and I'm very happy with it. The Sky box is dead easy to use, but it doesn't do very much.
What does the tivo do over the latest sky+ hd? Interested to know. Also interested in vm support things like whole series of boxsets on demand.